Underwater production satellite

ABSTRACT

This specification discloses a method for the production of subaqueous deposits of fluid minerals through a subsea satellite system. The wells are drilled in a circular pattern through a template on the marine bottom serving also as base upon which the satellite body is installed. The production and control passages of each of the wells are connected to production equipment within the satellite body by separate connector units, independently lowered into place from a surface vessel, to form portions of fluid paths between the passages within the subsea wellheads and the production equipment within the shell of the satellite. Such an installation permits production through the satellite, installed on the template base, after only one of the wells has been drilled and completed.

United States Patent [72] lnvcntor James T. Dean Dallas, Tex. 21 Appl.No. 740,521 [22] Filed June 27, 1968 [45] Patented Jan. 19, 1971 [73]Assignee Mobil Oil Corporation a corporation of New York [54] UNDERWATERPRODUCTION SATELLITE 2 Claims, 2 Drawing Figs. [52] U.S.Cl l66/.5,166/75 [51] Int. Cl E2lb 7/12, E2lb 33/035 [50] Field ofSearch 175/8. 9;l66/.5, .6 [56] References Cited UNITED STATES PATENTS 3,111,692 11/1963Cox l75/8X 3,261,398 7/l966 Haeber.. 166/.5 3,322,193 5/1967 Word 166/.63,355,591 11/1967 Bland ing etal. H 166/5 3384,169 5/1968 Leonard 166/.53,401,746 9/1968 Stevens et al. l66/.5 3;448,799 6/1969 Ahlstone 166/.5

ABSTRACT: This specification discloses a method for the production ofsubaqueous deposits of fluid minerals through a subsea satellite system.The wells are drilled in a circular pattern through a template on themarine bottom serving also as base upon which the satellite body isinstalled. The production and control passages of each of the wells areconnected to production equipment within the satellite body by separateconnector units, independently lowered'into place from a surface vessel,to form portions of fluid paths between the passages within the subseawellheads and the production equipment within the shell of thesatellite. Such an installation permits production through thesatellite, installed on the template base,.after only one of the wellshas been drilled and completed.

PATENTEUJAN -9 m 3.556208 sum 1 or 2 INVENTOR JAMES T. DEAN ATTORNEYPmmwqmsmn 3556.208

sum 2 or 2 JAMES T DEAN ATTORNEY awww This invention relates to a methodinvolving a subsea satellite designed to be independently connected to anumber of surrounding subsea wellheads and to control the productiontherefrom, th e su baqueous wells being produced through the subseasatellite wherein the produced fluids are separated, metered, and fromwhich they are transported to a storage facility. More particularly, theinvention'relates to a method utilizing a simplified means forconnecting a satellite separately to aplurality of closely surroundingsubsea wellheads.

2. Description of the prior Art I Since its inception, the offshore oiland gas industry has used bottom-supported above surface platforms asthe principal mechanism for the installation and support of theequipment and services necessary for the production of the subaqueousmineral deposits. As the industry has developed over the years, it-hasextended its search for offshore minerals from its birthplace. producingoil and "gas inthe shallow coastal waters off California and the Gulf ofMexico into areas where. because of excessive water depth and/or otherlocal conditions, the bottom-supported platform is not as economicallyor.

technologically feasible. i

A possiblesolution is to install the production facilities on afloatingplatform, as is described in the H. D. Cox*U.S. Pat. No. 3,I11,692, issued Nov. 26, I963, which can be maintained in position in afield by either a fixed multipoint mooring system of anchors and anchorlines, or by a dynamic positioning system. The above solution involvesthe expense of continuous maintenance and surveillance of the locatingsystem as well as the associated problemsand expense of maintaining themultiple, flexible lines connecting wellheads on the marine bottom withthe continuously moving floating production platform; and'the potentialhazard, of this system, to the hoses, in the event of a failure to thefixed mooring or dynamic positioning systems. In areas where there isextrememost necessitates the use of robots such asshown in the G. D.

Johnson US. Pat. No. 3,099,316, issudJuLBO, 1963. However, suchinstrumentalities are expensive and not without their own limitationsand maintenance problems.

Another solution is disclosed in the William F Manning Pat. applicationSer. No. 663,799, entitled Subsea Satellite Foundation Unit and Methodfor Installing a Satellite Body within said Foundation Unit, filed Aug.28, I967. A template is first set on the marine bottom and the wells aredrilled through the template. The Satellite is then set in the template,surrounded closely by the subsea wellheads. However, the satellitecannot be installed until all of thewells are completed. For purposes ofeconomy, the satellite should be installed as soon as the first well isdrilled and completed. Therefore, means must be devised for attachingeach well independently to the satellite body. This is also desirablefrom the point of view of ease of registry of the satellite body withthe wellheads.

SUMMARY OF THE INVENTION In accordance with the present invention, asubsea satellite body can be installed on a base template on a marinebottom prior to the completion of any producing wells therethrough.

Each well when completed produces through upstanding tub-' thereofstabbing over the tubing nipples extending upwardly" from the subseawellhead and the other endstabbing down over the vertical tubing nipplesextending upwardly from the upper end of the satellite body. 1

BRIEF DESCRIPTION OFTI-IE DRAWINGS FIG. 1 is a pictorial view of asubsea production system in accordance with the present invention; andFIG. 2 is a schematic diagram of a satellite station configuration forallowing the satellite body to be installed on a base template of asatellite station prior to the completion of any of the wells throughthezbase template. r

' DESCRIPTION OF THE PREFERRED EMBODIMENTS Now looking to FIG. I, asubsea system for producing fluid minerals, in particular gas and oil,from a subaqueous field by a plurality of subsea wellheads isillustrated. A plurality of subsea production satellite stations,generally designated [0. are

spaced across a marine bottom 12. each satellite station I0 comprising asatellite body 15 centrally-positioned within a circular group ofclosely'spaced subsea wellheads'l4. The produced fluids from thesubaqueous wells are directed through encircling subsea wellheads I4into the satellite body 15 of .the respective satellite station I0. Thefluids being produced from the subsea wellheads I4 of each circulargroup are combined within the respective enclosed satellite body 15'andta first'stage of separation (gravity) takes place. At least the;liquid portion is then directed to'a circular manifold I6 atop a centralbottom-mounted storage tank I) through a shipping line 18, one shippingline 18 extending from'each satellite station 10.

A floating master station 20, having power-generating and final stageseparation equipment thereon, as well as being .fitted out withoff-loading apparatus, is in fluid and electrical communication with thebottom-supported storage tank l7 through a tensioned tether pipe 22extending from the storage tank 17 to a point just beneath the turbulentsurface zone of the body of water and fixed at this point to a largesubsurface buoy 24. A flexible conduit 26, containing a plurality ofelectrical and fluid flow paths, extends from the upper end of thetensioned tether pipe 22 to the floating master station 20. The producedliquid, collected in the circular manifold I6, is directed to the masterstation through a main shipping line 27 supported along the length ofthetet'her pipe 22, and a fluid line forming a portion of the flexible"conduit 26. The produced liquid passes through the final stageseparation equipment on the master station 20'where the pressure isnormalized and dissolved gases are removed.The dead liquid is thentransported to storage within the storage tank 17 through a line of theflexible conduit 26 connected to an axial passage in the interior of thetether pipe 22.

In the upper left-hand comer of FIG. 1 is illustrated the drilling of awell through a satellite base template, generally designated 28, whichhas been previously installed on a marine bottom along with a shippingKline I8 for connecting a satellite station, when completed inconjunction with the template 28, with the storage tank I'I. A drillstring 30 is suspended from above the surface from a semisubmersibledrilling vessel 32 and extends through a blowout preventer stack 33mounted on one of a plurality of upstanding well conductor pipes 34forming a portion of the template 28. Illustrated in the lower portionof FIG. 1 is a manned submersible work vehicle, generally designated 36,of a type to be employed to assist in the subsea operations and for thedry transfer of personnel to the satellite station 10. The submersi blework vehicle 36 has a pair of articulated arms 38 and 40 carrying asocket wrench 42 and a vise grip tool 44, respectively. The submersiblework vehicle 36 is further equipped with a pivotable positioning motor46 on each side (one shown) to assist in locating the submersible workvehicle 36 adjacent a satellite station I0 firstly when subseaoperations are to be performed during the drilling operations and theintimes during maintenance and workover operations. A lower port 48 ofthe submersible work vehicle 36 is connected with a rear compartment(not shown) within the shell thereof to per mit a diver to be releasedat an installation site ifone should be Charles Ovid Baker, and EugeneL. Jones. and the references cited therein.

H0. 2 illustrates .a satellite station which is capable of beinginstalled prior to completing any of the production wells through thering 51 of the base template 28. The satellite body is held in thesatellite base 28 by a central sleeve 250 depending from the lower endof the satellite body and automatic spring-loaded latches (not shown)over the upper end of the well conductor pipe of the water well 52. Thelatches can be disabled by a hydraulic pressure applied through theconduit 252 extending between a manifold 254, forming a portion of theframing of the base template 28, at the inner end, and aquick-disconnect coupling section 256, at the outer end. The outer endof the conduit is supported by a skeletal frame 258 I to displace thecoupling section 256 outward of the well conduc tor pipes 34. Thearrangement of the equipment within the satellite body 15 is describedin detail in copending U.S. application, Ser. No. 740,783, filed Jun.27, l968. The connector units 54 are not permanently attached to thesatellite body 15 but instead are stabbed-over tubing nipples 260extending vertically out of the upper end of the satellite body 15. Whena well -is t o be completed through one of the upstanding wellconductorpipes 34, a wellhead 14 is first mounted on the respective wellconductor pipe 34. A connector unit 54 is later lowered from the surfaceto make the connection between the wellhead 14 and the satellite body15. The connector unit 54 consists ofa curved tubing section 56 and avertical lubricator section 58. The lower end of the lubricator section58 is stabbed over the tubing (not shown) extending vertically out ofthe upper end of the wellhead 14, while the outer vertical free ends ofthe curved tubing section 54 stabs over the respective ones of theupstanding tubing nipples 260 extending out of the upper end of thesatellite body 15. In this manner, with each connector section 54 beingindividually engaged between the wellhead l4 and the respectiveupstanding tubing nipples 260, greater tolerances can be allowed ininstalling the satellite body 15. Furthermore, an individual well can beproduced through the satellite station 10 while the remaining wells arestill being drilled and completed. The vertical orientation of thetubing nipples 260 extending vertically "into the satellite bodyIS'presents no problem, each of the TFL storage chambers 146 isreoriented into a vertical position so as to be coaxialwith therespective tubing nipples 260.

The vertical position ofthe storage chamber 146 permits the TFL tool 126stored therewithin to move easily into respective tubing nipples 260 sothat it can be pumped, under fluid pressure, through a full bend in thetubingsections 56 of the connector unit 54. Such a bend, of 180", willnot present any insurmountable problems requiring only that the wells bespaced out far enough from the satellite body 15 to obtain a 5 footradius bend in the conduit Stab-over connections, as discussed in thisapplication, are more fully described in the Manning application Ser.No. 663,799.

Although the present invention has been described in connection withdetails of the speciflc embodimen'ts thereof. it is to be understoodthat such details are not intended to limit the scope of the invention.The terms and expressions employed are used in a descriptive and not alimiting sense and there is no intention of excluding such equivalentsin the invention described as fall within the scope of the claims. Nowhaving described the apparatus and methods herein disclosed, referenceshould be had to the claims which follow.

lclaim:

l. A method for exploiting subaqueous deposits of fluid minerals througha subsea production station, including the following steps: I

a. setting a base template, through which wells are to be drilled, on amarine bottom beneath the surface ofa body of water; drilling at leastone well through said base template; completing said at least one wellwith a subsea wellhead supported on said base template;

d. releasably installing a production satellite body beneath the surfaceof said body of water on said base template; subsequent to step (d),fluidly connecting said at least one completed well with productionfacilities through said production satellite body by means of asubstantially rigid connector unit releasably connected between said atleast one subsea wellhead supported on said base template and saidproduction satellite body installed on said base template;

. subsequent to connecting said at least one completed well withproduction facilities through said production satellite body, drillingat least one more well through said base template;

completing said at least one more well with a subsea wellhead supportedon said base template; and

fluidly connecting said at least one more completed well with saidproduction facilities through said subsea production satellite body bymeans of a substantially rigid connector unit releasably connectedbetween said at least one more subsea wellhead supported on said basetemplate and said production satellite body releasably installed on saidbase template.

2. A method for exploiting subaqueous deposits of fluid minerals througha subsea satellite station, as recited in claim 1, wherein said at leastone well is drilled and completed, and" said production satellite bodyis installed, substantially from a floating station.

Patent No.

Inventor(s) James T. Dean Dated January 7 It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

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"In areas" should begin a new paragraph.

lls lt [I2 1] should should should should should should should shouldshould should should be be be be be be be .....34'--; "14" should be--14'- "54" should be "54'- -58'-- in both instances Signed and sealedthis 8th da of June 1971 (SEAL) Attest:

EDWARD M.FLE'I GHER.JR. Atteating Officer WILLIAM E. SCHUYLER, JRCommissioner or Pateint s

1. A method for exploiting subaqueous deposits of fluid minerals througha subsea production station, including the following steps: a. setting abase template, through which wells are to be drilled, on a marine bottombeneath the surface of a body of water; b. drilling at least one wellthrough said base template; c. completing said at least one well with asubsea wellhead supported on said base template; d. releasablyinstalling a production satellite body beneath the surface of said bodyof water on said base template; e. subsequent to step (d), fluidlyconnecting said at least one completed well with production facilitiesthrough said production satellite body by means of a substantially rigidconnector unit releasably connected between said at least one subseawellhead supported on said base template and said production satellitebody installed on said base template; f. subsequent to connecting saidat least one completed well with production facilities through saidproduction satellite body, drilling at least one more well through saidbase template; g. completing said at least one more well with a subseawellhead supported on said base template; and h. fluidly connecting saidat least one more completed well with said production facilities throughsaid subsea production satellite body by means of a substantially rigidconnector unit releasably connected between said at least one moresubsea wellhead supported on said base template and said prOductionsatellite body releasably installed on said base template.
 2. A methodfor exploiting subaqueous deposits of fluid minerals through a subseasatellite station, as recited in claim 1, wherein said at least one wellis drilled and completed, and said production satellite body isinstalled, substantially from a floating station.